The present disclosure relates to information processing apparatuses, information recording media manufacturing apparatuses, information recording media, methods, and computer programs. More particularly, the invention relates to an information processing apparatus, an information recording medium manufacturing apparatus, an information recording medium, a method, and a computer program that eliminate the unauthorized use of content and implement strict content usage management.
Various software data (hereinafter referred to as “content”), such as audio data, e.g., music, image data, e.g., movies, game programs, and various application programs, can be stored on recording media, for example, Blu-ray discs using blue laser light, DVDs (Digital Versatile Discs), MDs (Mini Discs), CDs (Compact Discs), as digital data. In particular, Blu-ray discs using blue laser light are high-density recording discs and can record a large volume of video content as high quality image data.
Digital content is stored in various information recording media described above and is provided to users. A user uses the digital content by playing it back on the user's PC (Personal Computer) or a player, such as a disc player.
Generally, the distribution rights of many content data, such as music data and image data, are owned by creators or sellers of such content data. Basically, therefore, certain usage restrictions are imposed when distributing content, that is, unauthorized copying is prevented by allowing the use of content only for authorized users.
According to digital recording apparatuses and recording media, images and sound can be repeatedly recorded and played back without a loss in quality. Thus, the distribution of illegally copied content via the Internet, the circulation of recording media, such as CD-R discs, recording copied content thereon, so-called “pirated discs”, and the use of copied content stored in hard disks of, for example, PCs are widespread.
DVDs or large-capacity recording media, such as those using blue laser light which have recently been developed, can record a large volume of data, for example, up to several movies, on one medium, as digital information. Since video information can be recorded as digital information as described above, it is becoming important to perform copyright protection by preventing unauthorized copying. Nowadays, to prevent unauthorized copying of digital data, various techniques for preventing unauthorized copying are practically applied to digital recording apparatuses or recording media.
For example, in DVD players, a content scrambling system is employed. According to the content scrambling system, data, such as, video data or sound data, encrypted and recorded on, for example, a DVD-ROM (Read Only Memory) can be descrambled for playing back the content.
In descramble processing, it is necessary to execute processing using specific data, such as a key, provided for licensed DVD players. A license is given to DVD players that are designed in compliance with predetermined operation rules, for example, agreeing not to perform unauthorized copying. Accordingly, licensed DVD players can descramble data recorded on a DVD-ROM by using specific data, for example, a given key, to play back images or sound from the DVD-ROM.
On the other hand, an unlicensed DVD player cannot play back data recorded on the DVD-ROM since it does not have a key for descrambling the scrambled data. In this manner, in the content scrambling system, DVD players that do not satisfy conditions demanded for receiving a license cannot play back digital data from the DVD-ROM, thereby preventing unauthorized copying.
However, such a content scrambling system is not a perfect system, and there are many content scrambling systems whose descrambling methods have already been deciphered and are distributed via communication means, such as the Internet. In this manner, once scrambling methods are deciphered, content is illegally played back or copied by unauthorized descramble processing, and the copyright or the right to use content is violated. Assuming that there is no perfect system, key revoking techniques are available as the countermeasures against deciphering scrambling methods. In those techniques, to revoke keys, it is necessary to identify in which devices hacking has occurred, and a method for tracing such devices is known as “traitor tracing”, as disclosed in the following patent publication.
However, in the method disclosed in the WO01/45410 reference, one screen is divided into a plurality of segments, which makes the management of keys complicated and also makes it difficult to speedily perform a playback operation. In WO01/45410, a specific configuration is not disclosed nor does it disclose how a playback order is determined.